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Concept explainers
(a)
To predict: The margin of win if the home team is favored by 3 points.
(a)
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Answer to Problem 1RE
Solution: The predicted value of the margin of win if the home team is favored by 3 points is 3.009.
Explanation of Solution
Given: The least-squares linear regression is provided in the question. The response variable is the winning margin and the explanatory variable is the spread.
Explanation: The value of the margin of winning can be obtained from the regression equation by substituting the value of the spread in the least-squares regression line. The predicted value of the margin of winning for the home team when the team is favored by 3 points can be calculated as follows:
(b)
To predict: The margin of win if the visiting team is favored by 7 points.
(b)
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Answer to Problem 1RE
Solution: The predicted value of the margin of win if the visiting team is favored by 7 points is 7.037.
Explanation of Solution
Given: The least-squares linear regression is provided in the question. The response variable is the winning margin and the explanatory variable is the spread.
Explanation: The value of the margin of win can be obtained from the regression equation by substituting the value of the spread in the least-squares regression line. The predicted value of the margin of win for the visiting team if the team is favored by 7 points can be calculated as follows:
(c)
To interpret: The slope.
(c)
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Answer to Problem 1RE
Solution: The slope can be interpreted as follows: if there is an increase of 1 unit of the variable
Explanation of Solution
Given: The least-squares linear regression is provided in the question. The response variable is the winning margin and the explanatory variable is the spread.
Explanation: The slope of the least-squares regression equation indicates the quantity of increase (decrease) in the response variable due to the 1-unit increase (decrease) in the value of the explanatory variable. In the provided equation, the amount of increase in the value of
(d)
To interpret: The y-intercept.
(d)
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Answer to Problem 1RE
Solution: The
Explanation of Solution
Given: The least-squares linear regression is provided in the question. The response variable is the winning margin and the explanatory variable is the spread.
Explanation: The
(e)
To interpret: The value of the coefficient of determination.
(e)
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Answer to Problem 1RE
Solution: The variation in winning margin is 39%, which can be explained by the least-squares regression equation.
Explanation of Solution
Given: The value of the coefficient of determination is 0.39.
Explanation: The coefficient of determination indicates that 39% of the variation is explained by the regression equation involving independent variable and the rest of the 61% variation remains unexplained.
Conclusion: From coefficient of determination, it is concluded that 39% of the variation in the winning margin is explained by the regression line.
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Chapter 4 Solutions
Statistics: Informed Decisions Using Data (5th Edition)
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